US1623588A - Process of making fibrous composition and articles produced therefrom - Google Patents

Description

' ,30 articles.

Patented Apr. 5, 1927. it

UNITED STATES. PATENT OFFICE.

EDWARD I. GEBMAIN, OF SAG-INAW, MICHIGAN, ASSIGNOB TO LOUIS GEBKAIN, m,

ALBERT A. GERMAIN, AND JOSEPH HEIDENKAMP, ALL OF PITTSBURGH, PENN-- SYLVANIA, AND EDWARD F. GERMAIN, OE

PROCESS OI MAKING FIBROU S COMPOSITION AND ARTICLES PRODUCED THEBEI 'ROI. I

No Drawing.

This invention relates to a composition of matter in the nature of a plastic mass capable of being molded under pressure while hot to form containers of various kinds-and.

other articles that are required to possess the qualities of resistance to action of acids,.

high dielectric and heat resistance, elasticity to resist shocks without cracking, .tensile strength and toughness.

The invention also relates to'a new method of manipulating the said composition or unded and before it is placed in the mold.'[ he new manipulation increases the physical plastic mass as soon as it has been comall parts of the mold cavity while the form-2 ing plunger is descending. My method of manipulation avoids the formation of air or. steam pockets in the finished articleand 1t.-

, enables quantities of the hot material to be prepared and kept on hand ready for the' molding ress, thereby increasing the daily output. a 1e methods heretofore commonly used required that each batch of material be placed in the press immediately a-fter mixing to prevent premature hardening and to better insure uniform quality in the finished Under my present novel, method a number of molding-press batches may be prepared and kept a considerable length of time without likelihood of hardening on the outside form consistency.

For the purpose of describing the novelty and utility of my invention I shall explain it with referencejo its employment in the making of multiple cell battery boxesffbecause" such boxes are'fairly representative of the kind of articles to the production of which my improved composition and method are especially well adapted.

, The objects of the--invention, therefore, with res set to manufacture of composition battery oxes are, to improve the physical strength of the box, its dielectric strength,

its resistance to heat and to the action of acid, and its flexibility throughout a wide range of temperature changes. Smoothness of the finished article is a characteristic of my invention as distinguished from the Application filed February a, sas. Serial m. 86,841.

and without impairing their original uni saeinaw, urcnr'oan, rnusrans.

wavy and imperfect surfaces usuall duced from bituminous mixtures mol ed under heavy pressure.

.These articles will be more clearly understood-after individual reference'has been made to each of the fpossesed by method. M p I I Physical strength-The composition box -must have great physical strength at normal boxes madeaccording to my new impact andto withstand such physical tests as the following: Dropper from a heightof be severe enough to chip off a smallcorner or an ed c. When the holding clamps are screwed own tightly upon the edge, or upon monly-emplo'yed for clamping battery boxes to automobile bodies, no sign of crushing, distortion under pressure, or weakness shall develop in the Dielectric strengtk.--The box. must have great dielectric strength to resist penetration by electric currents. The mixture herein described has under repeated tests shown a say, ten feet,- upon a concrete floor, the box should not crack, even though the impact principal characteristics atmospheric temperatures in order to resist i the handle of .the box, in the manner comso dielectric strength of up to twenty-fivei-y ,l

thousand volts, being many times that nec'essary to assure the requisite life and durability of a battery box.

Heat reszstance..-The battery box material .must have-sufficient heat resistance to withstand the heat generated during constant use both while charging and discharghotter-than would ever be experienced in 5 '95 put into a vise and pressure'applied in varyactual service, and the heated box is then mg degrees, there must be no deflection of the outsidewalls, partitions or bottom, un-

der squeezingestresses considerably greater use. Under severe stresses the partitions than would likely to .occur in practical and walls must show but very little deing the battery. It must, therefore, withflection. To assure strength and long life to the battery box the inside partitions must v Add'Nsi8tanm.-T0 assure that the box v not warp when the container is heated.-

is reasonably resistant to acid it must be able to withstand severe tests, one of which is immersion for about three months in hot sulphuric acid, fourteen hundred specific gravity, which is considerably stronger than ordinarily used in batteries, maintained dur-* ing all that time at one hundred fifty degrees Fahrenheit. At the end of that time its walls must show no signs of corrosion or weakening.

Flexibility-Under conditions of use a battery box'is subject to varying degrees of temperature and at the same time to hard usage, shocks, jolts from) road service, rough handling while being clamped into and taken out of battery box containers. Such'treatment necessitates material of considerable flexibility and resilience. For example,when used in an automobile in the winter reason, the liquid in the battery is liable to become low and if the battery liquid is weak, freezing may result. The flexibility of my material prevents broken cells or cracks in the container under such conditions.

Sm00t/z'ness.1f, as heretofore has been necessary with bituminous mixtures containing vegetable fibers such as paper or cotton linters, water is employed as an ingredient of the mixture, blow holes and sunken spots frequently appear on the finished article. These defects are caused by the presence of steam or gas within the mold. The result is a more or less porous, instead of an extreme- 1y dense article, and crazed surfaces. v

Finished articles having smooth surfaces ahd bodies homogeneous throughout are produced by my invention, notwithstanding I employ only dry ingredients. No addition of water is required in my mixture. In fact, I have proven that water, steam, '01 entrapped air in the mold are sure sources of trouble. I secure better results by substantially different means.

All of the foregoing desirable results are attained by the use of my improved composition or mixture as herein set forth. They have been arrived at only after long and painstaking research and experiment with the purpose of revealing the most satisfactory and economical ingredients for a mixture especially well adapted for the manufacture of battery boxes that fully meet the requirements already specified and to develop the best methods of manipulating the mixture for the production of molded articles having all of the desirable characteristics above mentioned.

My resultant invention is a new combination of ingredients which, considered separately and individually are each old in the art of making bituminous compositions, but combined, processed and manipulated in the manner which 1 will now describe, they comprise an entirely new industrial material.

This material. .molded under pressure, produces articles having all of the desired characteristics that have been enumerated in the foregoing statement of the objects of my invention.

Prepared or treated 'fibers.I first provide a fibrous filler which is capable of withstanding temperatures around four hundred degrees Fahrenheit without permanent loss of tensile sttength. Crude asbestos fiber, as

mined and commercially used meets the temperature requirement, butrit contains foreign elements, upon which sulphuric or other acids have a deteriorating effect.

By experiments and experience I have found that prepared or treated fiber, termed in the trade fibrous quartz is free from that defect and is suitable where, as in this case, conditions require high dielectric resistance and imperviousness to acid.

By treated fiber is meant fiber from which iron and impurities have been removed by chemical or other means.

"My new method and process includes, first, the thorough drying of the fibers to drive out all free moisture.

The treated and dried mineral fiber, or-

rather loose, feathery, or somewhat spongy character when in bulk is then preferably filled, or partly filled as to its interstices, by adding a' suitable fine-grained or pc vdered filler, such as fibrous quartz sand or silex, or silocel, preferably dried.

The treated asbestos fiber or so-called fibrous quartz has considerable tensile strength and the individual' fibers retain their strength after being heated. This material is acid proof and does not expand under heat sufficiently to cause breakage or cracking. If silocel, which is lighter than fibrous quartz, is mixed with the latter while dry, and the filler aggregate thus produced is then mixed, preferably while hot, with melted bitumen, the silocel is carried by means of the fibrous quartz into and through the bituminous mass while it is being kneaded. The silocel, being light, could not alone be readily mixed with bitumen by kneading. However, when fibrous quartz is present to carry the silocel, the filler a regate, quartz and silocel, mix thoroughly iind easily with bitumen. Air cells or pockets among the fibers are thereby avoided, the density of the finished product is increased, and a better surface is assured.

-Having thus prepared the filler aggregate I compound the bituminous binder as follows:

A bitumen of high melting point, such as gilsonite, is employed, also a bitumen of lower melting point and of greater fluidity in the melted state. Such other bitumen is preferably Mexican asphalt which is less brittle when cold than gilsonite and has greater resilience and flexibility. These two bitumens are placed in separate containers and reduced to the by heating.

The lower melting'point bitumen, Mexican asphalt, reduces the brittleness of the gilsonite and increases its strength and proper state of fluidity toughness. It also increases ease of flowing.

Consequently the fluid mixture more readily penetrates and thoroughly coats all the filler aggregate. I shall for convenience term the Mexican asphalt or its equivalent a tempering bitumen or vehicle because it carries the bituminous binder, gilsonite, into and through the mass of filler aggregate.

add mineral rubber, which in its melted state is more fluid than either the gilsonitc:

' hundred degrees Fahrenheit. Under proper high degree of elasticity to the gilsonite,

heat control it can be intimately mixed with the other materials and imparts hardnes",

and strength to the product in various and variable degrees, according to the proportions used.

Mexican asphalt melts at about two hundred or two hundred ten degrees Fahrenheit and when melted is readily mixed with melted gilsonite. While hot it increases the fluidity .of the gilsonite and during cooling it retards setting. In its solid state itis very elastic and consequently imparts a increasing the strength of the mass, rendering it more flexible and resistant to shocks and breakage. Mexican asphalt is acid proof and is a good vehicle for carrying the tiller aggregate through the fluid mass.

Mexican asphalt is very sticky when melted and if too much is used with gilsonite binder, it can not be satisfactorily kneaded. Instead of acting like a batch of bread dough which is in condition to be properly kneaded, the batch will act more like a batch of dough that is too wet and consequently sticky.

On the other hand, if too little Mexican asphalt is used the mixture of binder and filler aggregate acts like a batclrof bread dough that is too dry, and the mass becomes crumbly and has a tendency to divide or roll up into balls of different sizes. If that To further improve the fluidity I may also happens it is virtually impossible afterwards to combine these separate balls into a homogeneous mass without. first tearing the individual pieces apart. It is important to use just the right amount of Mexican asphalt, substantially as specified herein.

.Mineral rubber is very tough, yet flows. easily when melted. It

improves the fluidity of the gilsonite and Mexican asphalt binder. It likewise increases the capacity of the fluid to penetrate and cover the filler aggregate, and improves the smoothness of the finished surface.

v For making battery boxes having the physical characteristics .above described, I employ the ingredients in substantially the followingproportions by weight:

Per cent.

Gilsonite 25 Prepared or .treated asbestos fiber 25 -Silex, silocel, prepared or treated asbestos sand: 25

Mexican asphalt"; 20

Wax 5 If the binder is required to have a greater degree of elasticity and toughness, and a somewhat smoother surface, then the quantity of Mexican asphalt will be reduced from twenty per cent to, say, fifteen per cent, and mineral rubber will be added to the amount of five per cent of the total mass. I

If lightness is not of such great importance in the finished product, then silex or treated asbestos sand or fibrous quartz sand may be substituted for the silocel, the

amount by weight of silex being about thirty per cent more than the corresponding amount of silocel as specified above.

The proportions may vary somewhat according to the desired physical characteristics of the finished product, but in every case I proportion the tiller aggregate so as to produce a nonsticky batch that will knead I readily, but will not-crumble of form balls. Method of handZz'ng.The bitumens, namely, the gilsonite, Mexican asphalt and mineral rubber, having been melted in separate containers, are measured or weighed to the quantity desired and are mixed While hot, preferably in a kneading machine. Next the materials comprising the filler aggregate, namely, the treated asbestos fiber and silocel or asbestos sand, preferably hot, are weighed and added to the bitumens, not as a fibrous mass that requires tearing apart to permit its being impregnated with bitumen, as is common in some processes now in use, but as a loose agglomeration of practically separated fibers, each carrying in its interstices a portion of the powdered silocel or asbestos sand. These fibers are gradually sifted into the molten bituminous mixture. When the right amount of fibrous aggregate has been added, themass is thor- 'fibers of the filler aggregate.

' a somewhat solid state and fairly free from two hundred degrees Fahrenheit.

air pockets or pores, yet quite plastic Without being sticky. At this stage the mass can be dented, but will not flatten or settle down, and it can be put into a press and formed to the desired shape under heavy pressure.

Mineral rubber becomes fluid at about In making some kinds of' articles such as electric fuse plugs, battery box caps etc., I dispense with the mineral rubber. and useMexican asphalt alone as the tempering agent for the gilsonite.

A small amount of wax such as Montan Wax also may be used to facilitate pullin or extracting the finished articles from the moulds. The wax acts as a lubricant, and its use produces a smoother finished surface.

In carrying forward the usefulness of the mixture prepared as above described, by applying it to the manufacture of containers such as battery boxes having the physical characteristics specified at the commencement of this description, I have developed a new method of manipulating the mass of mixed material.

The new manipulation is especially adapted for increasing the physical strength of the walls, bottom and partitions of the battery box, and avoidance of air'holes and crazed surfaces in the product.

My improved method consists in the ma nipulation of a homogeneous mass, whichis formed of bitumen and fibers of any nature, and which have been mixed, puddled, kneaded, or agitated preparatory to moulding, as in the mixture already described. In such a mass the fibers due to mixing or agitation are disposed in all sorts of divergent positions, such as, horizontal, vertical, andmiscellaneous undeterminable positions. My new process consists in passing this homogeneous mass between rolls of any desired placement.

In this rolling process the greatest velocity of flow of the mass occurs in the area be tween the rolls, and the velocity decreases farther back into the mass. Consequently any fiber approaching the area of fastest flow is almost sure at some time during its passage to have one end in a faster flowing part of the mass than its other endqTherefore, there results a parallel rearrangement of the fibers. The fibers straighten out, that 15, take up positions parallel to the direction of flow throu h the rollers. The rolled sheet or layer as by far the greater part of its fibers running lengthwise and imbedded in the binder with ends overlapping likg reinforcing bars in a concrete floor s a The rolling pressure upon-the mass releases gases and pockets of air, making the. mass more compact and firm, and serving as a pie-compressing operation.

A sla'b or sheet of the .hot mixture is thus produced, free from entrained air and steam or gases, and having most of its constituent fibers running lengthwise. The fibers are more firmly embedded than they were after the kneading operation. These sheets of hot material can easily be kept hot for later use without danger of their surfaces becoming hardened, as nearly always occurs if a kneaded lump is allowed to cool, even slightly.

If the kneaded mass has been rolled, it can be kept on hand, hot, until the mouldingpress is ready to receive it, thus saving time ykeeping a supply of material ahead of the press requirements.

If the material is too hot it is weakened by moulding under pressure and if it is too cold or allowed to become chilled it become hardened and not plastic enough for mould ing. This is overcome in my method n-v cutting the material, immediately after being rolled, into units of cakes, blocks or sheets, and keeping these sheets hot, as by a hot box, coils or oven which is kept at a fairly uniform temperature. This tempers or anneals the material, permitting the naturalcohesion of the blocks to. take place to form one pre-compress'ed laminated mass, when piled and pressed. I

I next take the sheet of material as it comes from the rolls and cut it into slabs of proper size and shape to fit the mould. Several such slabs are preferably put into the mould, one on' top of another, adjacent slabs having their fibers directed at right angles, the total amount of material in all -the slabs equalling the amount required to greater strength than if not in the parallel arrangement above described.

Air pockets in the corners of the mould are avoided by this slab arrangement of the material in the bottom of the mould. Heretoforg a lump of hot material of the required size was deposited in the center of the mould,

and the first action of the die or plunger was to spread the mass over the bottom of the mould, followed by squeezing up into the sides and partitions. In every case, however, pockets of entrapped air were left in the voids of the-individual fibers with pul- .25 mass, rolling said mass into sheets, whereby ,to cause individual fibers therein to assume substantially parallel positions and serveas verized material and thereby cause the fibers to become carriers for said material, impreg nating the filled fibers with a hot liquefied bituminous binder, kneading the resultant reinforcing members for said sheet, cutting said sheet into slabs adaptedto fit a mold andsubjecting said slabs'to pressure, thereby causing the material of said slabsto flow {outwardly and upwardly and "assume the :forin of a molded article.

".able material which'consists in mixing dry 2. The process of making a plastic moldtough and adapted for the purpose intended,

acid-resistant fiber with dry pulverized acids resistant material to such extent as to sub} stantially fill the voids of the individual fibers with pulverized material and thereby a hot liquefied bituminous binder, and kneading the resultant mass, whereby it becomes rolling said mass into sheets to cause individual fibers therein to assume substanw tially parallel positions and serve as reinforcing members for said sheet, cutting said i sheet into slabs adapted to fit a mold, piling said slabs one upon the other and arrange with the fibers of aIternateslabs substantially parallel, subjecting the superposed slabs to pressure, thereby causing the material to flow outwardly and upwardly and" assume the form of a molded'article.

3. ,A container composed of a filleraggre gate in the form of treated asbestos intimately mixed with-pulverized earthy ma;- terial to substantially fill the'voids of the individual fibers, said filler comprising substantially fifty per cent, by weight, of the 3, f total ingredients and a bituminous binder intimately mixed with said filler and.c )n1-:' v

sisting of gilsonite twenty-five per cent, Mexican asphalt twenty per cent, and mineral wax five per cent, said material rolled into sheets and subjected to pressure causing the format v(f "said container. i- 7, I In testimony whereof, I afiix my signature;

' EDWARD F. GERMAIIT.

the material to flow and assume 40 cause. the fibers to become carriers for said material, impregnating the filled fibers'with